Method of and dental x-ray machine for producing x-ray pictures



July 19; 1949. 9. SM HERS 2, 7 ,7

METHOD OF, AND DENT X- M INE FOR,

PRODUCING X-RAY TU Filed Dec. 10, 1947 4 Sheets-Sheet 1 j ifia J r if 61? HfA/RY 5m rams B KBWM@ y 1949. H. SMATHERS 2,476,776

METHOD OF, AND DENTAL X-RAY MACHINE FOR, I

PRODUCING X-RAY PICTURES Filed Dec. 10, 1947 4 Sheets-Sheet 2 1. D 20 ml Ewan HENRYSMATHHS.

BY W

July 19, 1949. H. SM HEIRS 2,476,776

' METHOD OF, AND DENT X- MACHINE FOR,

I PRODUCING X-RAY TURES Filed Dec. 10, 1947 4 Sheets-Sheet 3 INVENTOR. f/[MQV 6M4 Tiff/R5 July 19, 1949. H. SMATHERS 2,476,776

METHOD OF, AND DENTAL X-RAY MACHINE FOR,

PRODUCING X-RAY PICTURES Filed Dec. 10, 1947 4 Sheets-Sheet 4 iffi i fifffiiffi;

INVENTOR.

HEM/F) S/MTHEHS BY Patented July 19, 1949 METHOD OF AND DENTAL X-RAY MACHINE FOR PRODUCING X-RAY PICTURES Henry Smathers, Charleston, S. C.

Application December 10, 1947, Serial No."790,808

19 Claims.

My invention relates to a method of, and a dental X-ray machine for, obtaining panoramic X-ray shadow photographs or pictures.

An important'object of the invention is to provide a; machine ofthe above mentioned character which will operate continuously for taking a panoramic X-ray shadow photograph or picture, indicating the exact 'conditlon ofeach and every tooth fend associated structures of the upper or lower jaws.

A further object of the invention is to provide a'machine of-the above mentioned character which may be operated to take individual X-ray shadow photographs or pictures of the selected teeth.

A further-object of the invention is to provide means tocause the X-ray tube to travel in a path around the face of the patient, corresponding to the shape'or contour of the face or the jaws.

A further object of the invention is to provide adjustable means for regulating the speed of travel of the X-ray tube around the face, for producing the correct exposure time.

A further object of the invention is to provide a guideelement which is to be applied to the face of the patient adjacent to the mouth and jaws and conforming to the shape or curvature of. the jaws, and. serving-to guide the tube in its travel around'the face.

A further object of the invention is to provide a machine of the above mentioned character which is relatively simple in construction, easy to rate, and reliable and economical in such operation.

Othe'r'objects and advantages of the invention will apparent during the course of the following description.

In the accompanying drawings forming a part of this application. and in which like numerals are employed to designate like parts throughout the Sarge,

Figure 1 is a side elevation of apparatus embodying my invention.

Figure 2 is a plan view of the same,

Figure 3 is a central vertical transverse section taken on line 3-4 of Figure l, the support arm or head being shown in elevation,

Figure 4 is a side elevation of the support arm or head and associated elements, parts in central vertical longitudinal section,

Figure 5 is a transverse section through the arm orhead. taken on line 5-5 of Figure 1,

Figure dis a side elevation of the cone for the X-ray tube.

Figure 7 is a plan view of the same, parts in section, taken on line 1-1 of Figure 6,

Figure 8 is a transverse section taken on line 8 -8 of Figure 6,

Figure 8 is an end elevation of the cone,

Figure 9 is a plan view of the cone, guide strip, and film, showing the cone in the starting position, v

Figure 10 is a transverse sectionthrough the guide strip and film, in place,

Figure 11 is a diagrammatic view of a circuit,

Figure 12 is an end elevation of the support arm and combined carriage and track,

Figure 13 is an enlarged fragmentary view of the disc included in the adjustable remote control and graduated in units of time.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention, the numeral I0 designates an elongated support arm or head, which is pivotally connected at one end to vertical swinging arms II, as shown at I2. The arms II are pivotally supported at their opposite ends, as is customary. The parallel arms II render it possible for the support arm I0 to be raised and lowered while maintaining the same horizontal and of 'course holding it against turning movement upon its longitudinal axis. Any suitable means may be employed to raise and lower the support arm Ill. The arms II constitute the usual arrangement used in connection with a dental chair for supporting implements.

At its free end, remote from the pivots I2, the support arm I0 is provided with a thumb screw I3, extending through an elongated slot I4 formed in a vertical bar I5, Figures 1 and 3, having a horizontal offset foot I6 at its lower end. The bar I5 is vertically adjustable with relation to the support arm I0 and may be clamped to the support arm by manipulation of the set screw I3. A vertical rod I1 is slideable Within a vertical opening I8 formed in the foot I6 and may be clamped in a selected adjusted position by a thumb screw I9. A rubber cup 20 is mounted upon the lower end of the rod II for engagement with the top of the head of the patient. It is thus seen that means are provided to properly connect the support arm I0 with respect to the head of the patient, and also to steady the head of the patient during the taking of X-ray shadow photographs or pictures.

The numeral 2| designates a main upper track or guide, adapted to swing horizontally. This track or guide has a vertical stub shaft 22, Figure 5, rigidly mounted upon one end thereof, at its top, and is also provided with a boss 23. This stub shaft extends into a vertical opening 24 formed in the support arm to. Figure 5, and is received in ball bearings 25, as shown. Agear 26 is rigidly mounted upon the stub shaft 22 and is confined between shoulders 21, thus holding the stub shaft against longitudinal movement. In this manner the track or guide 2| is pivotally connected with the support arm I to swing horizontally and is maintained parallel with the support arm. The gear 26 is driven by means to be described.

It should be noted that the vertically adjustable rod I1 is arranged in axial alignment with the vertical longitudinal axis of the stub shaft 22, Figures 1 and 12. This is important since it facilitates locating the head of the patient generally concentric with the pivot of the track or guide 2|.

The track or guide 2| is: generally inverted U-shaped in cross section, Figure 3, and includes vertical sides 28, having inturned horizontal flanges 29. A combined carriage and track 30 is provided for use in connection with the track or guide 2|. This combined carriage and track includes an upper carriage 3|, mounted to travel within the track or guide 2|, and having horizontal flanges 32 engaging bearing balls 33, as shown. Depending from the carriage 3| is a track including side rails 34, having horizontal flanges 35. For coaction with the side rails 34 is a lower carriage 36, having flanges 31, engaging bearing balls 39, as shown. The combined carriage and track 30 has openings 40 formed in the end thereof remote from the bar l5, to receive a pair of compressible coil springs 4|, the outer ends of which receive the reduced ends of adjustable screws 42 engaging the closed end 42' of the track or guide 2|. By manipulation of the screws 42, the tension of the springs 4| may be adjusted. As shown in Figure 1, these springs have shifted the combined carriage or guide 30 to the extreme position next to the bar l5, at which time the end of the combined carriage and track will engage a stop 43, secured to the track or guide 2|. The lower carriage 36 may be manually shifted longitudinally upon the combined track and carriage 30, and is locked to the same by a thumb screw 44.

Arranged beneath the lower carriage 36 and rigidly mounted thereon is an X-ray tube 45.

As more clearly shown in Figure 4, the support arm H) has a vertical shaft 46 J'ournaled therein. This shaft has a sleeve 41 rotatable thereon and the sleeve is journaled in a ball bearing 48. The sleeve cannot move longitudinally of the shaft 46. Rigidly mounted upon the sleeve 41 is a horizontal gear 49, having an upstanding clutch element 56, to coact with an upper clutch element which is splined upon the shaft 46 to move longitudinally thereof and turn therewith. A spring 52 shifts the clutch element 5| into enagement with the clutch element 56. It is thus seen that when the clutch elements properly en- I gage, the rotation of, the shaft 46 will be imparted to the gear 49, which engages and turns gear 26, which in turn will swing the track or guide 2|. The clutch element 5| is shifted from the clutch element 50 by a lever 53, arranged within the arm l0 and pivoted at 54. The lever 53 is swung in one direction to move the clutch element 5| from the clutch element 50 by a cam 54, rigidly mounted upon a rock shaft 55, extending to the exterior of the arm l0 and equipped with a handle 56, Figure 1.

Arranged above and rigidly mounted upon the arm I0 is a synchronous constant speed electric motor 51, having variable speed gearing 56 associated therewith. This variable speed gearing is driven by the armature shaft of the motor and in turn drives the vertical shaft 46. This gearing is adjustable within the ranges of 0 to 100 R. P. M. Any type of variable speed gearing may be used. A remote control 59 is provided for adjusting the variable speed gearing, including a disc 60, having a scale 6| graduated in seconds from 0 to 100. The remote control device is connected to the gearing 56 by cable 62. Any s'uitable means may be employed to turn the disc 60, and the scale 6| coacts with a stationary pointer 63. It might be stated at this point that when the disc 60 is adjusted so that the pointer 63 is at the 22 graduation of the scale, then the gearing 58 is so adjusted that the motor will drive the support arm from its starting position to its stopping position, within 22 seconds,-

In Figure 11, I have shown an electric circuit. This circuit includes leads 64, 64, and 65, 65'. The leads 64' and 65" extend to the opposite poles of the motor 51. nected in the leads 64 and 65, and a pilot light 61a is connected across the leads 64 and 65. A manual push button switch 68 is-connected in the lead 65. A motor switch 69 is connected in the lead 65. A pilot light 12 is connected across leads 64 and 65 and a pilot light 13 is connected across leads 64' and 65', A time controlled switch 1| is provided and is connected with the leads 64, 65, 64' and 65'. Wires 14 are connected.

with the time controlled switch 1| and lead to the cathode of the X-ray tube. The time controlled switch may be adjusted toopen at the end of a selected period, such astwenty-two seconds. Assuming that this switch 1| is now closed, and that switch 61 is closed and switch 68 is closed, then when switch 69 is closed, a circuit will be closed to drive the motor 51. In this circuit the current passes through lead 64; through switch 1|, lead 64', motor 51, switch 69.

' lead 65', switch 1|, and through lead 65. A circuit is also closed to the cathode of the X-ray tube, and in this circuit current passes through lead 64, switch 1|, one lead 14, the other lead 14, switch 1|, and through lead 65. At the end of twenty-two seconds, the switch 1| opens and the circuit to the motor 51 is opened and the circuit to the cathode of the X-ray tube also is opened; The controlled switch is common to the motor circuit and the X-ray tube circuit.

The X-ray tube 45 includes a detachable cone 15, which is preferably formed of a transparent plastic material. This cone has a bore 16'having four flat faces. These faces are made in the form of unbroken curves. The faces are assembled to form an elongated vertical opening or slot 11. These faces are lined with a lead covering 18. The shape or size of the slot 11 may be varied. The cone has a forward horizontal concave face 18, and rollers 19 are secured to the cone 15, at the end of face 18.

The numeral 60 designates a horizontal guide strip, which is preferably formed of some flexible or resilient transparent plastic material. This strip 86 is applied to the face and covers the mouth, and is pressed against the face so that it accurately conforms to the contour of the face. This strip may be held in place by adhesive tape v or by any other suitable means. The face strip should conform to the curvature of the face and the arrangement of the teeth, and this may be A service switch 61 is con- 4.

accomplished by using a flexible face strip. I also contemplate using a stiff face strip which has been previously formed to accurately conform to the curvature or shape of the face. This, face strip extends slightly beyond the posterior ends of the groups of teeth, as shown.

The operation of the apparatus is as follows:

When it is desired to take a panoramic shadow photograph or picture of the upper and lower teeth, an X-ray film A is placed within the mouth against the lingual surfaces of the teeth. This film extends vertically across the crowns of the upper and lower teeth and also extends throughout the entire length of the two groups of teeth. This film may be held in place by bite wing attachments B of the film. The clutch element 5| is now disengaged from the clutch element 50 and the support arm 2| may be manually swung so that the cone 15 will be opposite one end of the face guide 86 and the film A, Figure 9. The clutch element 5| may now be brought into driving engagement with the clutch element 50, but the motor 51 is still at rest. The combined carriage and track 30 is now held in the inner position in erigagement with the stop 43, by the springs 4|. The operator now releases the thumb screw 44 and shifts the carriage 36 toward the face strip 80, so that the rollers 19 engage the face strip 86. The rollers now engage the face strip adjacent to the one end of the face strip, Figure 9. The lower carriage 36 is now locked to the combined carriage and and track 30 by the manipulation of the thumb screw 44. The springs 4| are now pressing the rollers 19 into firm engagement with the face strip. Assuming that it will take 22 seconds to complete the exposure of the film, the disc 60 of remote control is adjusted so that the stationary pointer 63 is at the 22 point. This means that the adjustable gearing 58 is so adjusted that when the motor 51 is set into action, the motor within 22 seconds will swing the arm l0 throughout its entire travel, so that the cone 15 will travel from one end of the face guide 80 and film to the opposite end, thus completing the exposure. The disc 60 having been thus adjusted, the timing switch II was also adjusted so that the timing switch will retain the motor circuit closed for 22 seconds and will open the motor circuit at the end of the 22 seconds. This timing switch opens the motor circuit as well as the X-ray tube circuit. When the cone 15 is traveling about the face strip 80, it moves radially outwardly due to the eccentric shape of the face strip, and this outward movement is permitted by the springs 4| acting against the combined carriage and track 30. The main line switch 67 remains closed during these operations and the motor switch 69 is now closed, and then the manual push button switch 68 is closed. When the switch 69 closes, the motor is set into operation and the X-ray tube is set into operation. At the end of the 22 seconds, the motor circuit is opened and the X-ray tube is rendered inactive, and the relay is opened, and the push button switch 68 is returned to the opened position. The film having been subjected to the action of the X-ray, it is removed from the mouth in the conventional manner and developed in the usual way.

Should it be desired to take individual photographs instead of a panoramic photograph, the motor circuit switch 69 is opened and the arm i0 is manually shifted to the desired radial position with respect to the face, to bring the cone adjacent to the selected teeth. The lower carriage 36 is moved inwardly so that the com:- 16 is close to or in contact with the face, the face strip 80 then being omitted. The timing switch Ii is adjusted for the desired number of seconds of exposure and when the push button 68 is) closed, the X-ray tube is rendered active for the selected time, after which the switch II renders the tube inactive.

The device may also be used for the taking of continuous pictures of other parts of the human body, such as the spine, joints. or the like.

It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. A dental X-ray machine, comprising an arm to be substantially horizontally supported above the head of the patient, a substantially horizontal elongated track arranged near the arm, a substantially vertical pivot element connecting one end of the track with the arm so that the track may swing substantially horizontally, a depending bar mounted upon the arm near the pivot element and having a laterally offset foot, a head engaging element secured to the foot and in substantial alignment with the vertical longitudinal axis of the pivot element so that the head of the patient may be located generally concentric with the pivot element, an elongated combined track and carriage'mounted upon the track to move longitudinally thereof in a straight line toward and away from the pivot element, a spring connected with the combined track and carriage to automatically shift the combined track and carriage toward the pivot element, a carriage mounted upon the combined track and carriage to move longitudinally thereof in a straight line toward and away from the pivot element, adjustable means to clamp the carriage to the combined track and carriage, an X-ray tube mounted upon the carriage to be bodily shifted thereby, a flexible guide strip supported separately from the arm and contactin the face to conform to the shape and curvature of the face and extending over the mouth and cheeks, the carriage being longitudinally adjusted upon the combined track and carriage and clamped to the combined track and carriage for bringing the end of the X-ray tube into guiding engagement with the strip, the spring then shifting the combined track and carriage toward the strip causing the X-ray tube to remain in engagement with the strip, a motor mounted upon the arm, and means driven by the motor and connected with the track to swing the track substantially horizontally upon the pivot element.

2. A dental X-ray machine, comprising a substantially horizontal arm .to be supported above the head of the patient, asubstantially horizontal elongated track arranged near and beneath the arm, an upstanding pivot element carried by one end of the track and connecting the track a spring connected with the combined track and carriage to automatically shift the combined track and carriage toward the pivot element, a carriage mounted upon the combined track and carriage beneath the same to move longitudinally thereof in a straight-line toward and from the pivot element, adjustable means to clamp the carriage to the combined track and carriage in a selected .shape and curvature of the face and extending generally horizontally about the mouth and cheeks adjacent to the teeth, a motor mounted upon the top of the arm, and means driven by the motor and connected with the track to swing the track substantially horizontally upon the pivot element.

. 3. A dental X-ray machine comprising a substantially horizontal arm to be supported above the head of the patient, a substantially horizontal track arranged near the arm and having an end, a substantially vertical pivot element connecting the track with the arm so that the track may swing substantiallyhorizontally above the head of the patient, a depending member secured to the arm, a head engaging element carried by the depending member for engaging the head of the patient, a combined track and carriage mounted upon the track to move longitudinally thereof in a straight line toward and from the pivot element, a spring disposed between the combined track and carriage and the end of the track and serving to automatically shift the combined track and carriage toward the pivot 8 mounted upon the combined track and carriage beneath the same to move longitudinally thereof in a straight line toward and from the pivot element, a carriage mounted upon the combined track and carriage to move longitudinally thereof in a straight line toward and from the pivot element, adjustable means to clamp the carriage to the combined track and carriage, an X-ray tube mounted upon the carriage to be shifted bodily therewith, a flexible guide strip mounted upon the face of the patient adjacent to the teeth and conforming to the curvature of the face, the carriage being longitudinally adjusted upon the combined track and carriage and clamped in the adjusted position for bringing the end of the X-ray tube into engagement with the guide strip, the spring then shifting the combined track and carriage toward the guide strip to cause the X-ray tube to remain in contact with the strip, a motor mounted upon the arm and means driven by the motor and connected with the track to swing the same substantially horizontally upon the pivot element.

4. A dental X-ray machine, comprising a substantially horizontal arm to be supported above the head of the patient, a substantially horizontal elongated track arranged near and beneath the arm, an upstanding pivot element carried by one end of the track and connecting thetrack with the arm so that the track may swing substantially horizontally beneath the arm, a depending member secured to the arm near the pivot element, a head engaging element carried by the depending member for engaging the head of the patient, an elongated combined track and carriage mounted upon the track beneath the same to move longitudinally thereof in a straight line toward and from the pivot element, a spring connected with the combined track and carriage to automatically shift the combined track and carriage toward the pivot element, a carriage element, adjustable means to clamp the carriage to the combined track and carriage in a selected adjusted position, an X-ray tube mounted upon the carriage and extending below the same to be shifted bodily thereby, a guide strip supported separately from the arm and arranged close to the face of the patient and conforming to the shape and curvature of the face and extending generally horizontally about the mouth and checks adjacent to the teeth, a motor mounted upon the top of the arm, variable speed gearing connecting the motor and arm, adjustable means to regulate the action of the variable speed gearing, a motor circuit, and a time controlled device connected in the motor circuit.

5. A dental X-ray machine, comprising a support, shiftable supporting means mounted upon the support and movable with relation to the support, an X-ray tube mounted upon the adjustable supporting means, the adjustable supporting means permitting the X-ray tube being moved circumferentially about the face of the patient and generally radially with relation to such face, and a guide member corresponding generally to the contour of the face and supported near the face, said guide member being separate from the adjustable supporting means, the X- ray tube being shiftable toward the guide member so that a part of the X-ray tube engages the guide member, the guide member defining the path of travel of the X-ray tube about the face.

6. A dental X-ray machine, comprising a support, shiftable supporting means mounted upon the support and movable with relation to the support, an X-ray tube mounted upon the shiftable supporting means, the shiftable supportable means permitting the X-ray tube being moved circumferentially about the face of the patient and generally radially with relation to such face, a guide member corresponding generally to the contour of the face and supported near the face,

- said guide member being separate from the shiftable supporting means and not movable with the shiftable supporting means, the X-ray tube having a part to contact with the guide member, and yieldin means connected with the X-ray tube to bias the X-ray tube into contact with the guide member so that the guide member defines the path of travel of the X-ray tube about the face.

'7. A dental X-ray machine, comprising a support, shiftable supporting means mounted upon the support and movable with relation to the support, an X-ray tube mounted upon the shiftable supporting means, the shiftable supporting means permitting the X-ray tube to be moved circumferentially about the face of the patient and generally radially with relation to the face, a guide member corresponding generally to the contour of the face, means for holding the guide member in position near the face and holding it against movement with the shiftable supporting means, and yielding means connected with the X-ray tube to bias the X-ray tube toward the guide member so that a part of the X-ray tube is brought in contact with the guide member, the guide member definng the path of travel of the X-ray tube.

8. A dental X-ray machine, comprising shiftable supporting means, an X-ray tube mounted upon the shiftable supporting means, the shiftable supporting means permitting the X-ray tube to be moved circumferentially about the face of the patient and generally radial with relation to the face, a guide member corresponding generally to the contour of the face, means for supporting the guide member in position 'near the face and holding it against movement with relation to the shiftable supporting means, and yielding means connected with the X-ray tube to bias the X-ray tube toward the guide member so that a part of the X-ray tube is broughtsinto contact with the guide member, the guide member defining the path of travel of the X-ray tube.

1 9. A dental X-ray machine, comprising shiftable supporting means, an X-ray tube arranged beneath the shiftable supporting means and mounted thereon. the shiftable supporting means permitting the X-ray tube to be moved circumferentially about the face of the patient and generally radially with relation to the face, a guide member corresponding generally to the contour of the face and separate from the shiftable supporting means and arranged beneath the shiftable supporting means and held near the face, and yielding means connected with the X-ray tube to bias the X-ray tube toward the guide member so that a part of the X-ray tube is brought into contact with the guide member, the guide member definin the path of travel of the X-ray tube.

10. A dental X-ray machine, comprising a support, an elongated arm pivotally mounted upon the support to swing generally horizontally, a carriage mounted upon the arm to move longitudinally of the arm, a guide member corresponding generally to the contour of the face and separate from the pivoted arm and supported near the face and held against movement with the pivoted arm, an X-ray tube mounted upon the carriage, and yielding means connected with the carriage to bias the carriage toward the guide member to bring a part of the carriage into contact with the guide member, the guide member definin the path of travel of the carriage.

11. A dental X-ray machine, comprising a support, an arm pivotally mounted upon the support to swing generally horizontal, a combined carriage and track mounted upon the arm to move longitudinally thereof, a spring connected with the combined carriage and track to bias the same in a direction toward the face of the patient, a carriage mounted upon the combined carriage and track and movable longitudinally thereof, means to lock the carriage to the combined carriage and port, an arm pivotally mounted upon the support to swing with relation thereto, a carriage mounted upon the arm to move longitudinally of the arm,

yielding means connected with the carriage to bias the carriage in a direction toward the pivot of the arm, an X-ray tube mounted upon the carriage, means to swing the arm about its pivot and connected therewith and including a motor, a circuit for the motor, and a time controlled switch connected in the motor circuit.

13. A dental X-ray machine, comprising a support, an arm pivotally mounted upon the support to swing with relation to the support, a motor mounted upon the support, variable speed reducing gearing connected with the motor and with the pivoted arm so that the motor may swing the arm upon its pivot, means connected with the variable speed reducing gearing for controlling the speed of the same and graduated in units of time, and an X-ray tube mounted upon the pivoted arm.

14. A dental X-ray machine, comprising a support, an arm pivotally mounted upon the support to swing with relation thereto, co-acting clutch elements mounted upon the support, means connected with one clutch element to move it from the other clutch element, gearing connected with one clutch element and with the arm so that the rotation of such clutch element will swing the arm, driving means connected with the other clutch element and with the motor, and an X-ray tube mounted upon the pivoted arm. 1

15. A dental X-ray machine, comprising a support, shiftable supporting means mounted upon the support, an X-ray tube mounted upon the shiftable supporting means, and a guide element mounted upon the face of the patient and corresponding generally to the curvature of the face, the shiftable supporting means permitting of the movement of the X-ray tube circumferentially of the face and generally radial of the face, the X-ray tube having a part to contact with the guide member and be separated therefrom.

16. A dental X-ray machine, comprising a support, shiftable supporting means mounted upon the support for movement with relation thereto, an X-ray tube mounted upon the shiftable supporting means and including a cone, a guide element mounted adjacent to the face and corresponding generally to the curvature of the face, yielding means connected with the X-ray tube to bias the same in the direction of the guide element, the shiftable supporting means permitting of the movement of the X-ray tube circumferentially of the face and generally radially of the face, the end of the cone having a part to contact with the guide element so that the guide element defines the path of travel of the X-ray tube, the part being separable from the guide element.

17. An X-ray tube including a cone, shiftable supporting means connected with the X-ray tube to carry it, and rolling means mounted upon the cone to contact with a guide member separate from the supporting means.

18. An X-ray tube, a cone mounted upon the tube and having a recess which is substantially square in cross section, said recess having opposed faces which are cylindrically curved, lead linings for the opposed faces, the cone having an outlet opening passing through its forward end.

9. The method of taking a panoramic X-ray shadow photograph, comprising inserting a film within the mouth upon the lingual side of the teeth and having a length to extend substantially throughout the length of the group or groups of teeth, taking a guide strip corresponding generally to the curvature of the face and supporting such guide strip close to the face adjacent to the group or groups of teeth and arranging the same longitudinally of such group or groups, supporting an X-ray tube out of contact with the guide strip and moving the tube adjacent to the guide strip so that a part of the tube contacts with the guide strip and then shifting the tube longitudinally of the guide strip while exerting a. yielding pressure upon the tube in a direction toward the guide strip so that the guide strip defines the path of travel of the tube during the shifting movement, subjecting the film to the action of X-ray from the tube during the movement of the tube, and removing the exposed film from within the mouth.

HENRY SMATHERS.

(References on following page) Zulauf Mar. 7, 1922 12 Name Date Coolidge Sept. 21, 1926 Russell Sept. 13, 1932 Bucky Dec. 25, 1934 Levy Mar. 17, 1936 Graves Mar. 8, 1938 Schler Dec. 2, 1941 FOREIGN PATENTS Country Date Great Britain Apr. 3, 1930 

